


you are my sunshine (my only sunshine)

by Puffers_McMuffers



Category: Undertale (Video Game)
Genre: Alcohol Abuse/Alcoholism, Alternate Universe - Underfell (Undertale), Angst, Dirty Thoughts, Drunk Sex, Emotionally Repressed, F/M, Implied/Referenced Suicide, Self-Hatred, Temporary Character Death, Underfell Sans (Undertale), Underfell Sans/Reader - Freeform, Unhealthy Relationships, Unresolved Sexual Tension, Whump, and non-temporary character death, truly impressive amounts of self-loathing
Language: English
Status: Completed
Published: 2020-04-02
Updated: 2020-04-02
Packaged: 2021-03-01 05:15:54
Rating: Mature
Warnings: Major Character Death
Chapters: 1
Words: 3,228
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23449900
Author URL: https://archiveofourown.org/users/Puffers_McMuffers/pseuds/Puffers_McMuffers
Summary: because some people can't let themselves be happy
Relationships: Frisk/Sans (Undertale), Sans (Undertale)/Reader
Comments: 16
Kudos: 85





	you are my sunshine (my only sunshine)

_You are my sunshine_

* * *

It was always so dark in the Underground.

So fucking dark.

Which made sense, because as the name would suggest, the underground was _underground_ and there usually wasn't a lot of light down in the middle of mountains. Sure, they had their candles and lightbulbs and whatever other artificial light the wildlife provided, but there were entire sections of the underground that were pitch-black 24-7. The darkness seeped in from the woods and the waterfall, congealed onto the neglected sidewalks and clinging to his soggy shoes as he trudged through the small little towns and cities that made up their makeshift home. 

There was really very little to do in such a small space. He'd read everything there was to read, done every drug there was to do, fucked every fuckable person available, and knew _every single monster_ in existence on a first name basis. There was truly he hadn't seen anymore. Nothing left for him or anyone to do except wait for some unfortunate human to fall into the underground and kill them for their soul, so that one day they might be able to finally, _finally_ escape. It was really quite interesting to witness the depth of depravity people would sink to when they were desperate. Hunting _kids?_ That was some real fucking dark shit right there. 

Sans would know. 

He'd killed two already. 

Because he was one of the few monsters in the underground with the guts to do it. They'd capture them, sure, but actually _killing_ children was something that a surprising amount of people had trouble committing themselves to. Which he didn't understand, because they knew what would happen when they turned humans over to him. If they really cared about the surface so much they'd have the nerve to do it themselves and not hand off their problems to one of the few people in the underground who did not give a single shit about whether they made it out or not. 

Sure, Sans had wanted to see the sun when he was a kid. He’d heard so much about it from the few old enough to remember the surface, heard reverent recollections of its warmth and light. He'd read about it, too, when he was young and did things like read and study and ask for stories about the surface. He used to daydream of a golden sunrise breaking through the cotton-candy clouds flying languidly through endless azure skies _(This was back when he still used words like 'azure' and 'cotton-candy' to describe things)._ He'd feel the warmth of the sunlight spread through his cold, brittle bones, like stepping into a hot bath after a day working in the deep, slushy snow. He'd been little and stupid and that was so, so long ago, when he'd been scared of the dark

Now he didn't mind the darkness. In fact, he _thrived_ in it. He had the stomach to do things people didn't and that was valuable in a place like this. He didn't need _rolling fields of grass_ and _sunny beaches_ or anything else the humans had. Sans didn't like change and he didn't need anything or anyone to make him feel better. 

( _Sex, booze, and drugs hadn't. More living space certainly wouldn't.)_

He was fine in the darkness. 

Until _she_ showed up.

* * *

_My only sunshine_

* * *

She was, undoubtedly, the most annoying person he'd ever had the misfortune of meeting.

From the moment she'd first stumbled out of the ruins in that slightly singed, too big sweater, he knew she was going to be trouble. Humans always were- always killing and threatening and crying and causing general issues- but there was something about _her_ specifically that made a knot of dread curl in his stomach. And when she saw him she'd made this _face-_ fucking _smiled_ at him- that had made his throat close up and filled him with the overwhelming urge to throttle the life out of her pretty little yellow eyes.

So he killed her on sight and then five seconds later the world trembled _(what the fuck)_ and she was back, looking mildly surprised he'd had the audacity to impale her without so much as a _how do you do_ beforehand. 

_"Nice to meet you too," she said._

_He tried to kill her again. She dodged. The second time she wasn't so lucky, but it didn't matter, because she kept fucking coming back. Over and over._

_"fuckin' - stop fuckin' doin' that," he panted after she reappeared the fifteenth time, perspiration beading on his ivory brow. His lungs burned, every haggard breath of the frigid air scalding his throat. Every fight she lasted just a little longer, memorizing his attacks and slapping on bandaids every time he nicked her. By now half of her body was covered in them and quite honestly, it was nice to see he was making some impact._

_"You're the one who keeps killing me!" she replied defensively, almost laughing- what the hell, what the_ hell- _throwing up her arms in exasperation._

He killed her one more time for good measure before he gave up and tied her up, dragging her through the snow behind him as he tried to think up more permanent methods of murder. Except she wouldn't shut up, prattling on and on and on and yes, maybe she was a little bit funny, but _god._ That fucking mouth. He'd have dumped her in a ditch to rot, but she was the first _new_ person he'd had a conversation with in more than two decades and it was, frankly, not the worst thing that had ever happened to him. 

She wasn't anything like the people he knew. She was friendly, not entirely polite but genuinely _kind,_ which was fucking weird. Even stranger was her _persistence_ and determination to become buds with every asshole she ran into. Which meant, of course, she died over and over and over again. And came back over and over and over again, trying every tactic except for, you know, _fighting back,_ until Sans grew tired of having the world reset every time she kicked the bucket and started, like, protecting her or something. But only because death wasn't going to stick with her and he was sick of having to relive the same exact encounters a million times over. 

_"you're really gonna jus' let them kill you, huh?" he asked blearily, hands shoved in his pockets as she_ _re-applied bandages to her knees and hands. Sh_ _e glanced up at him, blowing a stray hair out of her face, and shrugged. This was the first break they'd taken in hours and she looked like shit, which was partly his fault, but that wasn't relevant._

_"Well, it'd be nice if they didn't."_

_"you ain't gonna fight back?"_

_"Nope."_

_He stared down at her for a long time, watching as she winced and prodded at the oozing gash across her palm._

_"you're a dumbass," he said finally._

_"Yup."_

There were a lot of annoying things about her. Perhaps the most annoying was that nobody else seemed to realize how _insufferable_ she was. She won everyone over eventually, despite Sans' best efforts. She was too charming, _disorienting_ , catching people off guard and forcing her way in like some sort of mildly pretty parasite. Even his own brother had fallen for her act. He'd even offered to let her stay at their house. _Sans_ house. _Papyrus,_ the one person Sans thought he could trust.It was like some sort of bad dream. 

If she'd been anyone else maybe it could've been bearable. But she _wasn't_ anybody else. She was just this bubbly, stupid piece of whatever that wouldn't stop following him around, like some stray puppy begging for scraps or whatever else it was stray dogs begged for. Attention, maybe. And everyone loved the dog, wanted to pet the dog and give it treats and kept asking if it was his and if they were allowed to touch it and, like, why would he even care- why would they _think_ he'd care- because the dog wasn't his and he didn't even like the dog, and he'd taken the dog analogy way too fucking far, hadn't he? 

She was just _too much._ Too _good._ When everybody was a terrible person he didn't seem all that bad in comparison. Not that he minded being bad, because that was just something he'd needed to become to survive, but they were just _too different_ and he didn't like change or things that were different. Different was dangerous. _She_ was dangerous.

_"Look, I made a snowman," she said as he stepped out of the house and onto the doormat. Her snowman was horribly misshapen and missing a massive chunk of its torso and she looked so proud of it. Her nose and ears were blotchy from the cold and she was shivering, grinning ear to ear and something inside of his chest squeezed at the sight of her._

_Sans turned back around and slammed the door behind him._

She refused to leave him alone. She introduced herself to others as his best friend, which was stupid, because even if Sans _had_ friends, he sure as hell wouldn't be friends with someone like her. Because he was probably two hundred years older than her, for one, which was weird, and she talked too much and didn't understand personal boundaries. And when she talked she favored the right side of her mouth, giving her a crooked expression that two years of braces had not fixed, and when she was thinking too hard she scrunched up her nose and squeezed her eyes real narrow. And she drank her coffee black but couldn't stomach booze because it was too bitter. And she had a little bit of an iron deficiency, so every time she stood up she'd stagger about until the blood came back to her head. And she used to want to be a ballerina when she was a little kid, but then she'd twisted her ankle and hadn't been able to dance for two months and by the time she'd gone back to dance class she didn't have her splits anymore and cried and cried and cried and decided to go to space camp instead, where she'd decided she'd wanted to be an astronaut until she heard about spaceships that had blown up and tasted freeze-dried food and decided that was not for her and he honestly wasn't sure why he knew any of this.

… fuck her, honestly.

* * *

_You keep me happy_

* * *

Sans didn't _dislike_ his life, but he wasn't sure he was happy with it. Content, sure, but not happy. 

Happiness was overrated. So fleeting. So fickle. So hard to find and keep, and Sans had never been one to much much effort into anything. Chronic laziness, he called it, although it was probably more like nihilism or defeatism or one of those other -isms that people didn't like to talk about. He liked things that were easy. Like alcohol and cigarettes and casual sex and pills and getting so shitfaced he couldn't move his legs. 

But the problem was that it wasn't enough anymore because all he wanted was _her._

He didn't know how it had happened and he didn't _want_ to know because it didn't change the fact that every time he thought about her he got all dizzy and warm and nauseous. And he thought about her a lot. Like, every waking moment and sometimes even when he was sleeping.

He couldn't get her out of his head. Couldn't stop thinking about her mouth and all the terrible, disgusting things he could do with it. Couldn't stop thinking about the dimple on the left side of her cheek that only appeared when she had her shark-grin on. Couldn't stop thinking about the time she'd fallen asleep on the couch and her shirt- _his shirt,_ because she didn't have clothes and Sans was a fucking saint- had ridden up and exposed all that _skin,_ soft and tanned and presumably warm to the touch. He couldn't stand the quiet anymore, accustomed to her rambles and high pitched, graceless laugh when he said something offensive she somehow found funny. He couldn't stand her _not being around._

When he was around he felt something he hadn't felt in a long, long time. And it wasn't a bad feeling, except that it was, because the last time he'd felt this way everything had gone to shit. He didn't _deserve_ to feel the way she made him feel. So he'd started avoiding her. Not like before. Like, _actually_ avoiding her. Which had gone well until it hadn't, because now she was spending time with _other people-_ people who weren't _him-_ and he couldn't stand seeing her with other people. Laughing with them. Touching them. It made him shake, red creeping into his vision because _he'd_ known her first. And that didn't give him a monopoly on her affection, of course, but the more people she met the less she cared about him and that shouldn't have bothered him but it did. 

Now when he saw her he was cold. Cruel, even, and he could see the hurt that flashed over her face every time he rejected her and it really was for the best. Because she was objectively a good person and Sans was nothing like her. Sans was a bad investment. He disappointed people constantly and she really did deserve better.

It was for the best, he told himself. 

* * *

_When skies are grey_

* * *

_She was waiting for him in his bedroom._

_"You're avoiding me," she stated bluntly, and Sans blinked, wondering momentarily if this was another one of those dreams of his. It was hard to tell, because he was really fucking wasted and why the fuck was she in his bedroom at two in the morning?_

_"is this real?" he asked her. He was swaying on his feet and hot, so hot._

_"You're avoiding me," she repeated._

_"no I'm not." Real convincing._

_She took a step forward and the door was closed and they were alone and it was very dark out but he could still see her face. She was mad at him. "Yes, you have. Why?"_

_"i dunno." She smelled like flowers and detergent and skin and it was really hard to think and god she was so pretty._

_"That's a shitty answer."_

_"okay."_

_"That's a shittier one."_

_"sorry," he croaked hoarsely._ _She was so close and Sans was shaking, breath coming out all wrong, too short, too hot, so_ hot. 

_She did not reply and then his mouth was on hers and they were staggering towards the bed, sloppy and desperate as his leg slotted between her own, fingers fumbling with his belt as his teeth worked away at her neck and there was just skin and sweat and warmth and it was too much, too tight-_

And it was-

It was hard to hate himself when she was wrapped up in his arms, soft and warm and all marked up with his teeth and fingerprints and shit, the sight of bruises on her skin shouldn't have made him feel so good, but it did, because as previously established, he was a terrible fucking person with no self control, couldn't even keep his fucking hands to himself for once in life because he was a fucking abomination, a waste of life and all he ever did was hurt and mangle and destroy and he wished, suddenly, that he'd never been born. 

" _Sans."_

_"yeah."_

_"Are you okay?"  
  
_

_"...yeah."_

  
  


* * *

_You’ll never know, dear_

_How much I love you_

* * *

He doesn't love her.

She's _something_ to him, he knows that. He cares about her more then he thought he was capable of caring. But he's 85% sure he doesn't love her, because Sans had never been taught how to love people and he's still selfish and mean and doesn't treat her the way you're supposed to treat the people you love. Whatever he feels for her isn't right. Isn't _pure._ Isn't good for either of them. 

He doesn't love her. Not the same way she loved him. When she loves people she _gives_ and all Sans knows how to do is _take._ So it's understandable why they don't work out.

… yeah. They don't work out. 

He's not sure why anyone is surprised. He still hangs around her every moment of the day and he still fucks her, like, often, and he gets real fucking mad if anybody even _looks_ at her, but no, they don't work out. Or they _won't_ work out, anyways. He knows whatever they have isn't going to last, because good things don't last for Sans. He always manages to fuck up somehow. Even when he actively tries not to, and believe him, he's _tried._

He's not sure what he said that last time that made her so mad. Maybe it wasn't anything he said. Maybe it was how he got out of her bed in the morning silently and stayed quiet when she went to go cry in the shower. Or how he drunk too much and kissed people who weren't her. How he was emotionally distant and too violent - always so violent- and never, ever soft. Maybe it was how he'd yelled at her for stupid fucking things like forgetting to lock the door or for talking to people who weren't him because he simply couldn't stand being happy.

He just wanted to get it over with. For her to realize that he's no good for her and ditch him before either of them get hurt more then they need to.

He doesn't know what finally breaks her, but one day he wakes up and she's gone.

She left a note ( _It's never good when they leave notes)._

_I hope you can be happy somewhere._

He stares at it for a long time, then crumples it up, lays back down on the bed and stares at the ceiling.

_(the bed is so big.)_

* * *

A few days later the barrier opens.

Nobody knows exactly what happened, but her body is laying in a pile of flowers at the mouth of the mountain and all the human souls they've collected are gone, hers included. The wound, they say, is self-inflicted. And that's troubling but he's sure she can explain it to him when she comes back, because she always comes back. And then he can tell her all the things he forgot to tell her before she left and they can go outside and do whatever and she can tell him all about how hard it was to smuggle out the souls from the palace and make it all the way to the gate by herself and all he has to do it wait for her to come back.

So he waits. And waits. And waits and waits until Papyrus has to pry him off her cold body and drag him away, trying to explain that the body isn't her anymore, that she can't come back, and he doesn't believe him, of course, until he catches a glimpse of the sunrise, saturated and real and _beautiful_ on the horizon and he turns and throws up all over his shoes, choking on vomit and tears that burn, burn, burn, because oh god, she's gone.

She's gone.

* * *

_please don't take my sunshine away_

**Author's Note:**

> that's it. that's the end of the story. it's a shitty story and there's no epilogue because there's nothing left to say.


End file.
